FORMELA JEAN FRANCOIS

SEC source: 0001209191-20-037372 · doc4.xml · derivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 18,900

Underlying: Common Stock · 18,900 shares

Expires 2030-06-15

F1 · derivative.exercise_date: This stock option will vest and become exercisable in full on the one year anniversary of the date of the award, or if earlier, the date of the Issuer's next annual meeting of stockholders following the date of the grant.

F2 · ownership.direct: This stock option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this stock option will be transferred to Atlas Venture Advisors, Inc. and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-000629 · doc4.xml · derivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 5,408

Underlying: Common Stock · 5,408 shares

Expires 2030-01-02

F2 · price: This stock option was issued to the Reporting Person, who elected to take stock options in lieu of $35,000 in cash compensation for services as a director, pursuant to the Issuer's non-employee director compensation policy. The proceeds of any sales of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Advisors, LLC and as such, the Reporting Person disclaims his beneficial ownership of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

F1 · derivative.exercise_date: This stock option shall vest in four quarterly installments on the last day of each calendar quarter during the calendar year subject to the Reporting Person's continued service as a non-employee director.

SEC source: 0001209191-19-038006 · doc4.xml · derivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 18,900

Underlying: Common Stock · 18,900 shares

Expires 2029-06-17

F1 · security: This stock option will vest and become exercisable in full on the one year anniversary of the date of the award, or if earlier, the date of the Issuer's next annual meeting of stockholders following the date of the grant.

F2 · security: This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Advisors Inc. and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any

F1 · derivative.exercise_date: This stock option will vest and become exercisable in full on the one year anniversary of the date of the award, or if earlier, the date of the Issuer's next annual meeting of stockholders following the date of the grant.

SEC source: 0000899243-19-015667 · doc4.xml · derivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 6,073

Underlying: Common Stock · 6,073 shares

Expires 2029-06-05

F1 · derivative.exercise_date: The shares underlying this option will vest and become exercisable in full on June 5, 2020 subject to the Reporting Person's continued service as a director through the vesting date.

F2 · ownership.direct: The reporting person is a member of Atlas Venture Associates IX, LLC ("AVA IX LLC") and is obligated to transfer the economic benefit, if any, received upon the sale of the shares issuable upon exercise of the equity grants to Atlas Venture Advisors, L.P. As such, the Reporting Person disclaims beneficial ownership to the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001209191-19-032080 · doc4.xml · derivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,000

Underlying: Common Stock · 19,000 shares

Expires 2029-05-20

F1 · derivative.exercise_date: This option was granted on May 21, 2019 with respect to 19,000 shares of Common Stock and vests in full on the earlier to occur of (a) the first anniversary of the grant date or (b) the date of the next annual meeting of stockholders following the date of grant.

F2 · ownership.direct: The reporting person is a member of Atlas Venture Associates IX, LLC ("AVA IX LLC") and is obligated to transfer the economic benefit, if any, received upon the sale of the shares issuable upon exercise of the equity grants to Atlas Venture Advisors, L.P. As such, the Reporting Person disclaims beneficial ownership of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001104659-18-045660 · a4.xml · nonDerivative · entry 2

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

F1 · security: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On July 16, 2018 AVA IX LP received 6,868 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $31.56 - $32.27, inclusive. The reporting person undertake to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (3) of this Form 4. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by AVA IX LP on March 23, 2018.

F1 · ownership.nature: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On July 16, 2018 AVA IX LP received 6,868 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001104659-18-045660 · a4.xml · nonDerivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,402

F1 · security: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On July 16, 2018 AVA IX LP received 6,868 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $30.56 - $31.55, inclusive. The reporting person undertake to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (2) of this Form 4. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by AVA IX LP on March 23, 2018.

F1 · ownership.nature: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On July 16, 2018 AVA IX LP received 6,868 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-18-019319 · doc4.xml · derivative · entry 4

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By Atlas Venture Fund VIII, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 454,550 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A, Series B and Series C Preferred Stock converted into Common Stock on a 5.5555-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series A, Series B and Series C Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date.

F1 · derivative.exercise_date: The Series A, Series B and Series C Preferred Stock converted into Common Stock on a 5.5555-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series A, Series B and Series C Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date.

F1 · derivative.expiration_date: The Series A, Series B and Series C Preferred Stock converted into Common Stock on a 5.5555-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series A, Series B and Series C Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date.

F2 · ownership.nature: These shares are held directly by Atlas Venture Fund VIII, L.P. ("Atlas Venture Fund VIII"). The sole general partner of Atlas Venture Fund VIII is Atlas Venture Associates VIII, L.P. ("AVA VIII LP"). Atlas Venture Associates VIII, Inc. ("AVA VIII INC") is the sole general partner of AVA VIII LP. Dr. Formela is a director of AVA VIII INC and disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund VIII, except to the extent of his pecuniary interest therein, if any. This report shall not be deemed to be an admission that Dr. Formela is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.

SEC source: 0000899243-18-019319 · doc4.xml · derivative · entry 3

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By Atlas Venture Fund VIII, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 1,050,891 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A, Series B and Series C Preferred Stock converted into Common Stock on a 5.5555-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series A, Series B and Series C Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date.

F1 · derivative.exercise_date: The Series A, Series B and Series C Preferred Stock converted into Common Stock on a 5.5555-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series A, Series B and Series C Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date.

F1 · derivative.expiration_date: The Series A, Series B and Series C Preferred Stock converted into Common Stock on a 5.5555-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series A, Series B and Series C Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date.

F2 · ownership.nature: These shares are held directly by Atlas Venture Fund VIII, L.P. ("Atlas Venture Fund VIII"). The sole general partner of Atlas Venture Fund VIII is Atlas Venture Associates VIII, L.P. ("AVA VIII LP"). Atlas Venture Associates VIII, Inc. ("AVA VIII INC") is the sole general partner of AVA VIII LP. Dr. Formela is a director of AVA VIII INC and disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund VIII, except to the extent of his pecuniary interest therein, if any. This report shall not be deemed to be an admission that Dr. Formela is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.

SEC source: 0000899243-18-019319 · doc4.xml · derivative · entry 2

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By Atlas Venture Fund VIII, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 2,326,567 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A, Series B and Series C Preferred Stock converted into Common Stock on a 5.5555-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series A, Series B and Series C Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date.

F1 · derivative.exercise_date: The Series A, Series B and Series C Preferred Stock converted into Common Stock on a 5.5555-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series A, Series B and Series C Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date.

F1 · derivative.expiration_date: The Series A, Series B and Series C Preferred Stock converted into Common Stock on a 5.5555-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series A, Series B and Series C Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date.

F2 · ownership.nature: These shares are held directly by Atlas Venture Fund VIII, L.P. ("Atlas Venture Fund VIII"). The sole general partner of Atlas Venture Fund VIII is Atlas Venture Associates VIII, L.P. ("AVA VIII LP"). Atlas Venture Associates VIII, Inc. ("AVA VIII INC") is the sole general partner of AVA VIII LP. Dr. Formela is a director of AVA VIII INC and disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund VIII, except to the extent of his pecuniary interest therein, if any. This report shall not be deemed to be an admission that Dr. Formela is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.

SEC source: 0000899243-18-019319 · doc4.xml · nonDerivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By Atlas Venture Fund VIII, L.P.

Disclosed balance after: 3,922,010

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series A, Series B and Series C Preferred Stock converted into Common Stock on a 5.5555-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series A, Series B and Series C Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial pubic offering. The shares had no expiration date.

F2 · ownership.nature: These shares are held directly by Atlas Venture Fund VIII, L.P. ("Atlas Venture Fund VIII"). The sole general partner of Atlas Venture Fund VIII is Atlas Venture Associates VIII, L.P. ("AVA VIII LP"). Atlas Venture Associates VIII, Inc. ("AVA VIII INC") is the sole general partner of AVA VIII LP. Dr. Formela is a director of AVA VIII INC and disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund VIII, except to the extent of his pecuniary interest therein, if any. This report shall not be deemed to be an admission that Dr. Formela is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.

SEC source: 0001104659-18-041218 · a4.xml · nonDerivative · entry 2

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

F1 · security: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On June 19, 2018 AVA IX LP received 6,686 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $28.28- $28.47, inclusive. The reporting person undertake to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (3) of this Form 4. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by AVA IX LP on March 23, 2018.

F1 · ownership.nature: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On June 19, 2018 AVA IX LP received 6,686 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001104659-18-041218 · a4.xml · nonDerivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,400

F1 · security: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On June 19, 2018 AVA IX LP received 6,686 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $27.28 - $28.27, inclusive. The reporting person undertake to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (2) of this Form 4. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by AVA IX LP on March 23, 2018.

F1 · ownership.nature: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On June 19, 2018 AVA IX LP received 6,686 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-18-015329 · doc4.xml · derivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 6,073

Underlying: Common Stock · 6,073 shares

Expires 2028-06-05

F1 · derivative.exercise_date: The shares underlying this option will vest and become exercisable in full on June 5, 2019, subject to the Reporting Person's continued service as a director through the vesting date.

F2 · ownership.direct: The reporting person is a member of Atlas Venture Associates IX, LLC ("AVA IX LLC") and is obligated to transfer the economic benefit, if any, received upon the sale of the shares issuable upon exercise of the equity grants to Atlas Venture Advisors, L.P. As such, the Reporting Person disclaims beneficial ownership of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001209191-18-031694 · doc4.xml · derivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,000

Underlying: Common Stock · 19,000 shares

Expires 2028-05-16

F1 · derivative.exercise_date: This option was granted on May 17, 2018 with respect to 19,000 shares of Common Stock and vests in full on the earlier to occur of (a) the first anniversary of the grant date or (b) the date of the next annual meeting of stockholders following the date of grant.

F2 · ownership.direct: The reporting person is a member of Atlas Venture Associates IX, LLC ("AVA IX LLC") and is obligated to transfer the economic benefit, if any, received upon the sale of the shares issuable upon exercise of the equity grants to Atlas Venture Advisors, L.P. As such, the Reporting Person disclaims beneficial ownership of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001104659-18-033996 · a4.xml · nonDerivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

F1 · security: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On May 16, 2018 AVA IX LP received 6,686 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.69 - $25.39, inclusive. The reporting person undertake to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (2) of this Form 4. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by AVA IX LP on March 23, 2018

F1 · ownership.nature: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On May 16, 2018 AVA IX LP received 6,686 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001104659-18-019521 · a4.xml · nonDerivative · entry 2

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

F1 · security: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On March 16, 2018 AVA IX LP received 39,245 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $23.70 - $23.86, inclusive. The reporting person undertake to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (3) of this Form 4.

F1 · ownership.nature: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On March 16, 2018 AVA IX LP received 39,245 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001104659-18-019521 · a4.xml · nonDerivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 36,628

F1 · security: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On March 16, 2018 AVA IX LP received 39,245 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $25.00 - $25.19, inclusive. The reporting person undertake to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (2) of this Form 4.

F1 · ownership.nature: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"), which is the general partner of Atlas Venture Fund IX, L.P. (the "Fund"). On March 16, 2018 AVA IX LP received 39,245 shares of the issuer's common stock from the Fund in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-17-025510 · doc4.xml · derivative · entry 11

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 602,589 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F2 · derivative.exercise_date: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F2 · derivative.expiration_date: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F4 · ownership.nature: Shares held by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Dr. Formela is a member of AVA X LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-17-025510 · doc4.xml · derivative · entry 10

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 513,318 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F2 · derivative.exercise_date: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F2 · derivative.expiration_date: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F3 · ownership.nature: Shares held by Atlas Venture Fund IX, L.P. ("Atlas Venture Fund IX"). The general partner of Atlas Venture Fund IX is Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-17-025510 · doc4.xml · derivative · entry 9

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 328,992 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F2 · derivative.exercise_date: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F2 · derivative.expiration_date: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F3 · ownership.nature: Shares held by Atlas Venture Fund IX, L.P. ("Atlas Venture Fund IX"). The general partner of Atlas Venture Fund IX is Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-17-025510 · doc4.xml · derivative · entry 8

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 246,272 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F2 · derivative.exercise_date: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F2 · derivative.expiration_date: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F3 · ownership.nature: Shares held by Atlas Venture Fund IX, L.P. ("Atlas Venture Fund IX"). The general partner of Atlas Venture Fund IX is Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-17-025510 · doc4.xml · derivative · entry 7

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 245,605 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F2 · derivative.exercise_date: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F2 · derivative.expiration_date: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F3 · ownership.nature: Shares held by Atlas Venture Fund IX, L.P. ("Atlas Venture Fund IX"). The general partner of Atlas Venture Fund IX is Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-17-025510 · doc4.xml · nonDerivative · entry 6

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 2,408,128

F1 · shares: Reflects shares of the Issuer's common stock that were purchased in connection with the Issuer's initial public offering.

F4 · ownership.nature: Shares held by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Dr. Formela is a member of AVA X LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-17-025510 · doc4.xml · nonDerivative · entry 5

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,979,557

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · price: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F4 · ownership.nature: Shares held by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Dr. Formela is a member of AVA X LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-17-025510 · doc4.xml · nonDerivative · entry 4

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,376,968

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · price: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F3 · ownership.nature: Shares held by Atlas Venture Fund IX, L.P. ("Atlas Venture Fund IX"). The general partner of Atlas Venture Fund IX is Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-17-025510 · doc4.xml · nonDerivative · entry 3

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 863,650

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · price: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F3 · ownership.nature: Shares held by Atlas Venture Fund IX, L.P. ("Atlas Venture Fund IX"). The general partner of Atlas Venture Fund IX is Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-17-025510 · doc4.xml · nonDerivative · entry 2

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 534,658

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · price: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F3 · ownership.nature: Shares held by Atlas Venture Fund IX, L.P. ("Atlas Venture Fund IX"). The general partner of Atlas Venture Fund IX is Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-17-025510 · doc4.xml · nonDerivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 288,386

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · price: Amount of underlying securities reflects the application of the applicable conversion ratio as set forth in the Issuer's Amended and Restated Certificate of Incorporation in effect immediately prior to the closing of the initial public offering (as adjusted by the 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017). Each series of preferred stock was automatically converted upon the closing of the Issuer's initial public offering without payment of further consideration and had no expiration date.

F3 · ownership.nature: Shares held by Atlas Venture Fund IX, L.P. ("Atlas Venture Fund IX"). The general partner of Atlas Venture Fund IX is Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001104659-17-044530 · a4.xml · nonDerivative · entry 3

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 3,579,788

F1 · security: Represents shares sold by Atlas Venture Fund IX, L.P. ("Atlas IX"). Atlas Venture Associates IX, L.P. ("AVA IX LP") is the general partner of Atlas IX. Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of the securities held by Atlas IX, except to the extent of his pecuniary interest therein, if any.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $16.00 - $16.325, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (4) of this Form 4.

F5 · ownership.nature: Represents shares held directly by Atlas IX. The general partner of Atlas IX is AVA IX LP. AVA IX LLC is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of the securities held by Atlas IX, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001104659-17-044530 · a4.xml · nonDerivative · entry 2

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 3,659,788

F1 · security: Represents shares sold by Atlas Venture Fund IX, L.P. ("Atlas IX"). Atlas Venture Associates IX, L.P. ("AVA IX LP") is the general partner of Atlas IX. Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of the securities held by Atlas IX, except to the extent of his pecuniary interest therein, if any.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $16.00 - $16.70, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (3) of this Form 4.

F5 · ownership.nature: Represents shares held directly by Atlas IX. The general partner of Atlas IX is AVA IX LP. AVA IX LLC is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of the securities held by Atlas IX, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001104659-17-044530 · a4.xml · nonDerivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 3,699,788

F1 · security: Represents shares sold by Atlas Venture Fund IX, L.P. ("Atlas IX"). Atlas Venture Associates IX, L.P. ("AVA IX LP") is the general partner of Atlas IX. Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of the securities held by Atlas IX, except to the extent of his pecuniary interest therein, if any.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $16.50 - $17.25, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (2) of this Form 4.

F5 · ownership.nature: Represents shares held directly by Atlas IX. The general partner of Atlas IX is AVA IX LP. AVA IX LLC is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of the securities held by Atlas IX, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001209191-17-033985 · doc4.xml · derivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,000

Underlying: Common Stock · 19,000 shares

Expires 2027-05-17

F1 · derivative.exercise_date: This option was granted on May 18, 2017 with respect to 19,000 shares of Common Stock and vests in full on the earlier to occur of (a) the first anniversary of the grant date or (b) the date of the next annual meeting of stockholders following the date of grant.

F2 · ownership.direct: The reporting person is a member of Atlas Venture Associates IX, LLC ("AVA IX LLC") and is obligated to transfer the economic benefit, if any, received upon the sale of the shares issuable upon exercise of the equity grants to Atlas Venture Advisors, L.P. As such, the Reporting Person disclaims beneficial ownership of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001209191-17-020050 · doc4.xml · nonDerivative · entry 2

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

F1 · security: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $13.86 - $14.33, inclusive. The reporting person undertake to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (3) of this Form 4.

F1 · ownership.nature: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001209191-17-020050 · doc4.xml · nonDerivative · entry 1

FORMELA JEAN FRANCOIS · CIK 0001030575 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 5,504

F1 · security: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $13.75 - $14.02, inclusive. The reporting person undertake to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (2) of this Form 4.

F1 · ownership.nature: Represents shares sold by Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Formela is a member of AVA IX LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any.